The effects of global warming will be costly, but it will also be expensive to cut CO₂. Together these two pieces of information give us no clear idea as to what we should do. If we focus on how extensive the damage from global warming will be, we will be inclined to intervene now and in a big way--but this approach ignores the cost of such intervention. On the other hand, if we focus on the high cost of reducing CO₂ emissions then we are inclined just to let things take their course--but this approach ignores the ever increasing damages from warming. So the question is in reality how best to act.

Bjørn Lomborg describes the Greenhouse Effect and discusses issues surrounding the Kyoto Agreement.

We could, of course, achieve almost instantaneous stabilization of the atmosphere's CO₂ content and achieve a slow stabilization of the climate by banning all use of fossil fuels right now, but at the same time doing so would practically bring the world to a standstill. This would have incalculable consequences, both economic, health-related and environmental (note that initially we are simply deliberating which solution is globally and collectively the best.) We could also choose to let things take their course, continue our ever increasing emissions of CO₂ and then pay the costs by adapting society in 2100 and later by building dikes, moving island populations, changing farming methods, etc.

	Thinking Points
	Is the "green mentality" based on an idealised picture of the world? The environmental reality, from the Ice Age to the age of global warming, appears to point to a world of extremes. Are "right-wing" and "left-wing" positions tenable by those committed to the environment?

In between these two extremes, of course, we have the option of reducing CO₂ emissions somewhat and accepting some greenhouse warming. There are also a whole series of further considerations to be made as regards when prospective cuts should be made, but basically it is a choice as to the degree we want to reduce CO₂ emissions and pay up now, and the degree we are willing to live with higher temperatures at a later date. (It can generally be said that given a certain stabilization, the cheapest solution is to postpone cuts until as far as possible into the future, because this will facilitate the reduction of capital adaptation costs.) So the question is whether between stabilization of the climate and business-as-usual there can be found a solution that does not upset present society too much but does not result in too high climatic costs in the future either.